Apparatus for generating an air barrier



June 21, 1966 H. M. MELZER 3,256,798

APPARATUS FOR GENERATING AN AIR BARRIER Filed Sept. 17, 1963 2 Sheets-Sheet l mm 3.3 g i g i \Ti ---a -Jb El l I H INVENTOR.

HERMAN M. MELZER I L B H y fidt d.

Attorney June 21, 1966 H. M. MELZER 3,256,798

APPARATUS FOR GENERATING AN AIR BARRIER Filed Sept. 17, 1963 2 Sheets-Sheet 2 /N VEN TOR.

HERMAN M. MELZER A Horney United States Patent 3,256,798 APPARATUS FOR GENERATING AN AIR BARR Herman M. Melzer, 2109 Gordon Ave., McKeesport, Pa. Filed Sept. 17, 1963, S91. No. 309,523 Claims. (Cl. 98-36) This invention relates to apparatus for generating a flow of air which is directed across a doorway or other access opening to form a barrier to the passage of heat and also serves as a barrier for resisting penetration by insects, flies and other foreign material such as dirt, pollen and the like.

The advantages of an air curtain or air door, as it is sometimes referred to in the art, are many fold. For example, it is possible to eliminate doors and other obstructions in the doorway and provide easier access through the doorway thereby increasing the rate of movement and the ease of movement. Whereas the air flow is effective as a means for maintaining a temperature differential and for resisting penetration by insects and the like, it is almost imperceptible by traffic walking through the doorway and it is, therefore, unobjectionable from. the standpoint of interference with traffic.

It has further been found, that by maintaining open doorways and other access opening, traflic can be induced more readily into stores, shopping areas and the like.

It is, therefore, one of the primary objects of the present invention, to provide a new and improved apparatus for generating a flow of air which provides a barrier within a doorway or access opening permitting the maintenance of either refrigerated air conditioning or heating within an enclosure and without loss of such cooled or heated 'air within the enclosure to the outside, as would otherwise occur in the absence of such air barrier.

It is a further object of the present invention, to provide an air flow generating device which can be mounted over doorways to freezers, cold rooms and the like, and which is adapted to maintain a substantial temperature differential whereby warm air is effectively excluded from the refrigeration room or cold room. and thereby prevents loss of valuable refrigerated cold air and further reduces the extent of condensation of warm, moist air within the cold room on the cooling coils and other portions of the cold room, impairing the efficiency of the refrigerating apparatus.

It is a still further object of the present invention to provide an apparatus which is inexpensive in operation and construction and can be readily mounted to maintain either a steady state or on-off operation for an air curtain apparatus which effectively separates areas between the doorway or access opening.

It is a still further object of the present invention to provide a new and'improved apparatus for generating an air barrier which is silent in operation and is readily adjustable to provide an air flow of the correct intensity and dimensions to suit a substantial variation in size of doorway or the like.

It is a still further object of the present invention to provide a novel adjustment for an apparatus of the type described in which the degree of flow as well as the dimensions of such flow is specifically designable to a given operating condition and location.

It is a still further object of the present invention to provide a novel mounting mechanism for the blowers and actuating mechanisms therefor disposed within a volute casing of the apparatus so as to increase the efficiency of operation, and to provide a steady flow of air through the apparatus under superatmospheric pressure of substantially constant value.

Additional objects and features of the present invention Patented June 21, 1966 will become apparent from a consideration of the following description, which proceeds with reference to the accompanying drawings, wherein:

FIGURE 1 is a front elevation view of the apparatus, with a part of the casing broken away to illustrate the internal blower and actuator mounted internally therein;

FIGURE 2 is a side view of the apparatus looking at the right-hand end of FIGURE 1;

FIGURES 3, 4 and 5 are section views taken on line III-III, IV-IV and VV, respectively, in FIGURE 1;

FIGURE 6 is a transverse sectional view of the inlet structure at the opposite ends of the casing shown in FIGURE 1 and taken on line VI-VI of FIGURE 5; and,

FIGURE 7 is an isometric view of the complete air door structure.

Referring now to the drawings, particularly FIGURE 1, the apparatus is designated generally by reference numeral 16 and is comprised of a casing 12 having an internal chamber 14 of volute cross section (FIGURE 4) lined with a suitable sound-suppressing material, such as fiber glass, fiber wool or the like, the exact composition of which is not an essential part of the present invention.

The volute shape of the chamber 14 (FIGURE 4) together with barrier 18 at the bottom of the volute cross section chamber 14 enables the build-up of internal sup eratmospheric pressurewithin the chamber 14 during clockwise rotation, indicated by arrow 20 (FIGURE 4) by two blower wheels 22, 24 which are driven by a motor 26 having drive shaft connections 28 and 30 with said blower wheels 22 and 24, respectively. Each blower wheel (FIGURES) is comprised of a hub 32 having spaced apart drive arms 34 connected at their outer peripheries by a series of impeller blades 38 (FIGURE 3), the impeller blades being both curved and disposed at an angle so that they exert a pumping action drawing air from opposite ends 44-, ,46 of the casing (FIGURE 1) and effecting a build-up of superatmospheric pressure within chamber 14 which reaches an equilibrium when the outfiow of air through slot 48 (FIGURE 1, FIGURE 4) equals the rate of inflow from openings 44,46, at the ends of the casing.

The two blower wheels 22, 24 are fastened by set screws 50 to their respective drive shafts 28, 30 and the motor, is mounted to the back plate 52 (FIGURE 4) of the casing by two projecting arms 54 and 56 which are disposed with their minor dimension in the path of air flow (FIGURE 3) so as to provide the least possible obstruction to the flow of air. Thus, both the motor and the pumping elements driven thereby are mounted through arms 54 and 56 which are secured through flanges or the like and metal screws 60 to the backing 52, which thereby carries the weight of both the motor and pumping elements and positions them at the proper location within the volute chamber 14 and provides a journal mounting for rotation of said blower wheels 22 and 24.

Within the discharge slot 48 are a number of adjustable vanes 66 which are mounted through companion lugs 68 on mounting pivot pins 70, each vane 66 being movable as indicated by dotted line positions 72, 74 (FIGURE 1) to adjust the direction of flow of air so that the flow will cover all portions of the doorway or access opening. Each vane 66 is individually positionable and the friction from its associated mounting pin issufiicient to maintain the position of the vane against further movement. In this way, the dimensions of the air curtain, by reason of the direction of flow of air at the discharge slot 48 can be regulated so as to cover all portions of the doorway and the air is directed either from above or at the side of the doorway and substantially traverses all portions thereof.

At the openings 44, 46, are a plurality of concentric frusto-conically shaped channel members 80, 82, 84 and screws or the like 98 (FIGURE 1).

' 3 86 (FIGURE 6) mounted on struts 90 which support all of the channel members 80-86 and hold them in fixed spatial relation to provide annular inlet spaces between adjacent ones of channels 80-86. All of the channels are in turn secured to the end plates 94, 96 by metal A cylindrical member 100 is mounted adjacent the channel 80 for the purpose of directing the flow of air into the path of the rotating impeller blades 38, the circumference of the cylindrical member 100 being slightly larger than the circle of impeller blades (FIGURE 1) and terminating just adjacent the impeller blades 38 so as to direct the flow into the path of the rotating blades. The inflow of air thereby proceeds with minimum turbulence into the pathway of the impellers and becomes compressed and produces a superatmospheric internal pressure within chamber 14.

The rate of inflow of air, is regulated by positioning the two semicircular bafiles or dampers 102, 104 to throttle the flow of air or allow free access of air through the annular passageways between adjacent ones of the conically shaped members 80-86. The bafllles 102, 104 are angularly movable on hinge connections 108 and 110 at their opposite respective ends (FIGURE by means of arms 112, 114 which are mounted on pivots 116, 118 and are caused to move about said pivots by pinion 122, 124 connections with a rack 126 movable by a worm 128 on a fixed stem 130 which is rotatable by a knob 132. The construction is shown and described in detail in US. Patent No. 3,010,381 Circulation Control Damper, issued November 28, 1961 to Frederick F. Glass.

Once the batfles 102, 104 are positioned, they will hold their adjusted angular position until moved to a different angular position by rotation in one direction or the other of knob 132. It has been found that for maximum efiiciency, the baflles 102, 104 are disposed angularly to the inflow of air, 'i.e., in a slightly closed position from the dotted full open positions indicated by the dashed lead lines for reference numerals 104 and 106 in FIG- URE 6, it having been found that the air will thereby be directed slightly against the cylinder 100 which then channels the air directly into the impeller blades 38 rather than the air flowing to the center of rotation of, the blades 38 and there, by turbulence, eventually working out into the path of the blades 38. Continued movement of the bafiles, however, to the full line position shown in FIGURE 6 will, by means of throttling the flow, eventually reduce the rate of inflow and reduce the equilibrium internal pressure within chamber 14 and correspondingly reduce the force of flow out of the discharge slot 48 and reduce the intensity of air flow for the air curtain. One of the purposes of reducing the intensity of flow would be to make the air .curtain less obtrusive to those persons walking through the doorway, and another reason being to suppress any operational sound.

In operation, the device is mounted through a mounting flange 120 having openings 122 which are adapted to receive bolts or the like (not shown) which support the apparatus above the doorway or whatever other location of use. The motor 26 is then energized from a control box 126 having a suitable electrical conductor 128 which connects with the power source for operating the motor 26.

As the motor 26 operates, the blowers 22, 24 are actuated and the impeller blades 38 are rotated clockwise (FIGURE 4) drawing air from the inlet openings 44, 46 at the opposite ends of the casing through the annular passages provided between adjacent ones of the members 80-86. The volute shape of the inner instead, produces a build-up of pressure causing an outflow of air through the discharge slot 48, there being eventually reached, an equilibrium internal pressure which is achieved by a balance between the inflow of air from the ends of the casing and the outflow of the air from the discharge slot 48. Depending upon the contour of the access opening or doorway, the baffles 66 are adjusted individually so that a flow of the discharged air from the slot 48 will traverse the entire outline of the doorway or access opening.

The intensity of flow of air is regulated by turning the knob 132 to rotate the semicircular baflles 104, 108 from the dotted line position shown in FIGURE 6, slightly angularly to the full line positions and so moved angularly, they will provide a range of flow control positions from the maximum inflow of air positions. To throttle the flow, the knob 132 is turned so as to suecessively move the baflles toward the annular inflow passages to throttle the inflow of air, until reaching the full line position where they completely shut off any inflow of air and reduce the air flow to a minimum value.

As the air is caused to flow inwardly and is then discharged from the slot 48, the air flow is relatively unimpeded by the mounting arms 54, 56 since they are aligned so that only their thickness dimension is presented to the line of travel of the air. For this reason, the unimpeded flow of air is relatively undeflected internally of the chamber and thus conserves the efficiency of operation and produces minimum turbulence and Waste power.

I have found it advisable in some instances to provide a cushion mounting between the mounting ends of the mounting arms 52, 54 and the motor 26 which in turn suspends the blowers thereby, so that in operation the apparatus is relatively noiseless.

Although the present invention has been illustrated and described in connection with a single example embodiment, it will be understood that this is illustrative of the invention and is by no means restrictive thereof. It is reasonably to be expected that those skilled in this art can make numerous revisions and adaptations of the invention to suit individual design preferences, and it is intended that such revisions and variations will be included within the scope of the following claims as equivalents of the invention.

I claim:

1. A device for generating an air flow of prescribed dimension, velocity, and direction to form a barrier which is extended across an access door or other opening to form an obstruction for insects and serving as a barrier to the transition of heat thereacross, comprising a casing having an internal volute-shaped chamber terminating in a narrow slot forming an outletfrom said volute chamber, a plurality of spaced directing vanes disposed in said slot angularly movable therein to shape the flow of air as it passes through the slot, a pair of spaced pumping elements'located interiorly of said chamber, mounting means for said pumping elements which extend through said chamber in the form of relatively thin members having plate-like configuration extending across said chamber and disposed edgewise to the flow of air within said casing, said mounting means serving to mount said pair of spaced'pumping elements within said chamber, means for securing said mounting means to said casing through a wall thereof which suspends said device in its operative position motor means for operating said rotatable pumping means and also disposed within said casing, two inlets located one at each end of said casing to provide inflow of air to the interior of said casing and comprised of a plurality of annular concentric inlet passages, and angularly movable baflie means for controlling the effective cross section of said concentric passages.

2. A device for generating an air flow of prescribed dimension, velocity, and direction to form a barrier which is extended across an access door or other opening to form an obstruction for insects and serving as a barrier to the transition of heat thereacross, comprising a casing having an internal volute-shaped chamber terminating in a narrow slot forming an outlet from said volute chamber, a plurality of spaced directing vanes disposed in said slot angularly movable therein to shape the flow of air as it passes through the slot, a pair of spaced pumping elements located interiorly of said chamber, mounting means for said pumping elements which extend through said chamber in the form of relatively thin members having plate-like configuration and disposed edgewise to the flow of air within said casing, motor means for operating said rotatable pumping means and also disposed within said casing, two inlets located one at each end of said casing to provide inflow of air to the interior of said casing and comprised of a plurality of annular concentric inlet passages, angularly movable bafile means for covering and uncovering and thereby controlling the eflective cross section of said concentric inlet passages, means for mounting said baflle means centrally of said inlet passages, and manually adjustable means having a threaded member movable into and out of said casing for angularly locating sa-id bafile means defining the effective cross sectional area for :the inflow of air into said chamber.

' 3. A device in accordance with claim 2 including an angular cut-ofif batfle disposed adjacent said slot and projecting inwardly into proximity with said rotatable pumping elements to prevent recirculation of air through said volute casing whereby air is continuously drawn into said casing through said inlets and is discharged through said outlet slot.

4. A device in accordance with claim 2 including means for supporting said device at the side thereof adjacent the slot whereby the outflow of air forms a covering at the outline of the access opening.

- 5. A device in accordance with claim 2 including a lamination of sound-suppressing material which forms a covering over the interior surface of said casing.

References Cited by the Examiner WILLIAM F. ODEA, Primary Examiner. JOHN F. OCONNOR, Examiner. 

1. A DEVICE FOR GENERATING AN AIR FLOW OF PRESCRIBED DIMENSION, VELOCITY, AND DIRECTION TO FORM A BARRIER WHICH IS EXTENDED ACROSS AN ACCESS DOOR TO OTHER OPENING TO FORM AN OBSTRUCTION FOR INSECTS AND SERVING AS A BARRIER TO THE TRANSITION OF HEAT THEREACROSS, COMPRISING A CASING HAVING AN INTERNAL VOLUTE-SHAPED CHAMBER TERMINATING IN A NARROW SLOT FORMING AN OUTLET FROM SAID VOLUTE CHAMBER, A PLURALITY OF SPACED DIRECTING VANES DISPOSED IN SAID SLOT ANGULARLY MOVABLE THEREIN A SHAPE THE FLOW OF AIR AS IT PASSES THROUGH THE SLOT, A PAIR OF SPACED PUMPING ELEMENTS LOCATED INTERIORLY OF SAID CHAMBER, MOUNTING MEANS FOR SAID PUMPING ELEMENTS WHICH EXTEND THROUGH SAID CHAMBER IN THE FORM OF RELATIVELY THIN MEMBERS HAVING PLATE-LIKE CONFIGURATION EXTENDING ACROSS THE CHAMBER AND DISPOSED EDGEWISE TO THE FLOW OF AIR WITHIN SAID CASING, SAID MOUNTING MEANS SERVING TO MOUNT SAID PAIR OF SPACED PUMPING ELEMENTS WITHIN SAID CHAMBER, MEANS FOR SECURING SAID MOUNTING MEANS TO SAID CASING THROUGH AS WALL THEREOF WHICH SUSPENDS SAID DEVICE IN ITS OPERATIVE POSITION MOTOR MEANS FOR OPERATING SAID ROTATABLE PUMPING MEANS AND ALSO DIS- 